I have a habit of picking up seeds/pods from wherever I happen to be, and of sticking them along with pits, etc from edibles into pots to see what grows. (one species to a pot) This sprouted last October. The picture is what it looks like now (April)...I have no idea what I planted. Thank you for your help.
It looks rather like Ricinus communis, probably one of the darker leaved varieties (because of the red stems and slightly dark appearance of the leaves). Leaves have 7 or 8 points, sometimes 9, but if it is that, bear in mind its seeds are somewhat toxic if consumed. It should produce better colour on the leaves outdoors because it needs sun and bright light, which yours doesn't look to be getting as a houseplant, so you might want to move it outside when the weather has warmed up. Often grown as an ornamental annual, it may be perennial in warm regions. Image of Ricinus communis 'Red Giant' as an example here https://www.amazon.co.uk/Plant-World-Seeds-Ricinus-Communis/dp/B00YL4YWZU